Radial pump with trunnion mounting of shift ring



March 6, 1945. o. M. SUMMERS 3 L RADIAL PUMP WITH TRUNNION MOUNTING OF SHIFT RING Filed Sept. 14, 19 42 2 Sheets-Sheet 1 INVENTOR OTTO MURRAY sumnms, 1

*W ATTORNEYS March 6, 1945. o; M. SUMMERS 2,371,073

RADIAL PUMP WITH TRUNNION'MOUNTING of SHIFT RING Fild Sept. 14, 1942 2 Sheets-Sheet 2 INVENTOR o'r'ro MURRAY sunmras,

BY WM W A ATTORN EY5 e g g the same. occurred in maintaining proper parallelism be- Patented Mar. 6, 1945 .nsnnn. PUMP wl'rn 'raumon MOUNTING F SHIFT RING om M. Summers, Mount'Gilead, 0hio,'assignor to The Hydraulic Development Corp., Mount Gilead, Ohio, a corporation of Delaware Application September 14, 1942, Serial No. 458,218

3 Claims. (1 103-161) This invention relates to pumps for producing fluid pressure, and particularly pumps of the type having a primary and a secondary rotor with radial pistons therebetween' The pumps may be of the variable delivery type having a one-way delivery, or may be of the reversible variable delivery type.

Heretofore, pumps of the variable delivery type that are constructed and arranged to produce relatively high fluid pressures became difllcult to a shift toward neutral position after they had been in use for sometime. In pumps'of the type having a primary and secondary rotor it is conventional to use a shift ring for supporting the secondary rotor, and for movingthe same relathe various parts over prolonged periods of use.

An object of the invention is to provide a raidal pump. unitv having the shift ring thereof mounted on journals for decreasing the frictional 5 -resistance to movement of the shift ring.

Another object of the invention isto provide a means for mounting the shift ring of a variable Y delivery fluid pump wherein the clearance betive to'the primary rotor to change the output delivery of the pump. The shift ring has been provided with flat surfaces that slideupon flat surfaces provided on the pump housing when the ring is shifted by suitable control elements Considerable difliculty has tween the flat surfaces on the housing and the shift ring during their manufacture because of the relatively large size of fluid pumps that are delivering large volumes of fluid. The flat surfaces are spaced apart from one another in parallel relation from about 5 inches to as much as 34 inches in the larger type pumps. -'I'he problem of maintaining accurate dimensions between the flat surfaces is' also acute. v

When fluid pumps are operated against relatively high fluid pressure, considerable heat is developed in the pump that is transmitted to the shift ring causing the same to expand. The

- pump'body, of course, is exposed to the tem- 'perature of the room atmosphere which many tween the flat-surfaces on the shift ring and the flat surfaces on the pump housing is reduced to an extent that the surfaces bind. Also,- as the pump is used the surfaces tend to wear and there-.

' by produces play between the surfaces on the shift ring and-thehousing so that the torque reaction produced by the pump mechanism ca'use'the surfaces on'the shift ring to cock-with respect to'thesurfaces on the housing and again produce abinding action;

It is, therefore, an object of this invention to,

- valve spindle II. The valve spindle l1 1; duced diameter portion, that t tapered roller. bearings 10 and "for I a P imary rotor II. The tapered roller bearing a provide a means for mounting the shift ring-of will maintain the accuracy of clearance between tween the mounting means on-the shift ring and the means on the pump housing can be increased without losing any accuracy of control over the movement of the shift-ring, whereby expansion of the shift ring mounting means due to temperature differential between the mounting means and the housing of the pump willnot effect the freedom of action between the shift ring and the pump housing.

Another object of the invention is to provide a variable delivery pump particularly of the radial type wherein the shift ring ismounted upon journals to permit freedom of movement of the shift ring axially of the journal and wherein the drive shaft or spindle of the rotor of the pump provides means to prevent rotation of the shift ring, or pump unit upon the journals.

Further objects and advantages willbecome apparent from the drawings and the following description.

In the drawings: Fig. 1 is a vertical cross-sectional view of a fluid pump' embodying features of this invention taken substantially along line l- -l of Fig. 2.- Fig. 2 is a horizontal cross-sectional'view of a pump embodying features of this invention taken substantially along line 2-: of Fig. 1.

Fig. 3 is a transverse cross-sectional view of the Joumal mounting for the shift ring taken along line 3-4 of Fig. 1.

The pump of this invention consists'of a substantially cylindrical casing II that has end walls It and I2 secured thereto by means such as the bolts It. The casing II is provided with a hollow interior ll that receives hereinafter described. U

The endwall II is provided with a boss "that has an internal bore ll adapted to receive the II and ilare preloaded between-an end 'cap 2| secured. to the end of the-spindle portion ll by of the bolts-22 ands ring fl positioned a inst the inner surface of the boss ll inrthe end plate H. An adiustingnut'll is threaded the pump mechanism 7 upon the threaded portion 26 of the valve spindle adjusting nut 24 and a shaft seal 32 is provided around the drive shaft 21.

The primary rotor 25 has a plurality of radially disposed cylinder bores '33 in which the pistons 35 are adapted to reciprocate. The cylinder bores 33 communicate with arcuate valve passages 34 and 36 alternately provided in the spindle portion I8 that communicate with passages 31 and 38, respectively, for delivering fluid to anddischarging fluid from the various cylinder bores 33. The valve spindle I! is provided with suitable p assages, one of which is shown at 39 for connecting the passages 31 and 38 with suitable inlet and discharge passages, not shown, in the boss l5 for the end plate H. Y

The cylinders 35 drive a secondary rotor 40 which consists of end plates 4| and 42 that are retained in spaced relationship by means of the crosshead thrust guide blocks 43; bolts 44 extend- 'shift ring by means of bolts 53 and 54, respectively. The journals 5| and 52 are slidably disposed inbores 55 and 56, respectively, provided in'diametrically opposite walls of the casing Ill. The bores 55 and 56 are preferably cylindrical in shape as shown in Figures 1 and 3. The bores 55 and 56 for the journals 5| and 52 can be produced in the casing either by separate operations to accurately align the bores 55 and 56., or by a continuous operation that proceeds through both bores 55 and 56 to insure their axial alignment. The journals 5| and 52 support the shift ring within the casing l and absorb the torsional reaction produced within the pump by means of the radially operated pistons regardless of the eccentric position of the shift ring with respect t the primary rotor. The journals and 52 provide a supporting means for the shift ring 50 that has 'a relatively long surface of contact to minimize wear at any particular point. Also, the

use of journals 5| and 52 within the bores 55 and 56 provides means whereby the clearance bestationary part on the casing-Ill can be more ancurately maintained. It is much easier to main-' tain the diameter of a bore accurate than it is to maintain parallelism between flat surfaces that area substantial distance fromone another such as often occurred in pumps of large capacity. Again, when the shift ring of a radial type pump is mounted on journals as disclosed in this invention, he, clearance between the journal and its ing of the pump because there is a greater surface area of they journal that will support the shift ring. If there was any substantial clearance provided between the flat supporting surfaces of 5 the shift ring and the flat surfaces on the casing of the former pumps there would be a substantial binding between the surfaces that prevented smooth operation of the shift ring. In effect the former flat surfaces produced merely a line contact for. the shift ring when the clearance between the surfaces was sumcient to permit complete freedom of action over all conditions when the surfaces cocked with respect to one another.

The journals of this invention will permit the use of relatively small'clearances between the journal and its mounting bore and yet prevent binding between the journal and the bore due to expansion of the journal upon a temperature increase of the pumping mechanism, the small journals expanding considerably less than the expansion of the shift ring as formerly arranged. Therefore, the invention provides greater freedom of action between the shift ring and the supporting casing for the same to .produce a smoother operation of the shift ring by control mechanisms that are connected thereto.

An extension 63 on the journal 5| engages the control member 5'l that is slidably disposed in a casing member 58 provided for the control member 51. The casing 58 is secured to the casing III by means of bolts 59.

The control member 60 is slidably disposed in a casing 6| and engages an extension 62 provided on the journal 52. The extension 62 passes through an oil seal 64.- The casing 6| is secured to the'pump casing III by means of bolts 65.

The control members 51 and 60 maybe oper ated in any suitable fashion to change the position of the shift ring 5ll with respect to the pri- 0 mary rotor 25. In some instances the control member 60 may be spring pressed to urge the v shift ring toward full stroke position and the control member 51 can be manually or automati- M cally operated to oppose the control member to shift the ring 50 toward neutral position, or the control member 60 can move the shift ring 5|] past neutral to th opposite eccentricity with respect to the primary rotor 25 and thereby re- 50 verse the delivery from the pump.

The journals 5| and 52 reciprocating in their bores 55 and56 would have a tendency to trap fluid that leaks behind the journals. To prevent any trapping of fluid behind the journals 5| and 55 52 they are provided with passages 66 and 61 the shift ring 5|). v

Whilethe form of the apparatus disclosed and described herein constitutes a preferred form, no yet, it is to be understood that the use of journals v for supporting a shift ring is not limited to the type of pump disclosed herein, the actual construction of the pumping mechanism being disclosed as one of a number of types of radial pumps that use a shift ring for changin the eccentricity of the pump members for changing the volume delivery of the pump. v

- The journals 5| and 52 are preferably pircular in form since this is the easiest type of structure 70 to produce. Since they are circular in form, the shift ring 50- could rotate upon the journals. However, the valve spindle l1 and the drive shaft 21 prevent such rotation of the primary and secondary rotors and. the shift ring 50 upon the ,i0 Whiletl'ie pump unit disclosed and described that permit escape of fluid into the interior of in this invention constitutes a preferred form, yet the structure is capable of'substantial me chanical alteration without departing from the spirit of the invention, and all such modifications as fall within the scope of the appended claims are intended to be included herein.

- Having thus fully described my invention what I claim as new and desire to secure by Letters Patent is: i

1. In a variable delivery pump of the type described, a casing having a chamber, variable delivery pumping mechanism in said chamber, including a primary roto'r, means journalling said primary rotor for rotation about a first axis, a secondary rotor, a shift ring rotatably supporting said secondary rotor on a second axis parallel to said first axis, reciprocable pumping elements extending between said rotors, and means mounting said ring for shifting along a third axis lying in the plane of said ring and normal to said first and-second axes, said means comprising aligned journals extending from opposite sides of said ring, each journal slidably fitting a corresponding bore in said casing whereby the separation of said first and second axes may be varied, said journals constituting the sole means for supporting said ring and secondary rotor. I

2. In a variable delivery pump of the type described, a casing having a chamber, variable delivery pumping mechanism including a primary ing said secondary rotor within said chamber on a second axis parallel to said first axis, reciprocable pumping elements extending between said rotors, and means mounting said ring for shifting along a third axis lying in the plane of said ring and normal to said first and second axes, said means comprising aligned journals extending from opposite sides of said ring, each journal slid- ,ably fitting a corresponding bearing surface on said casing whereby the separation of said first and second axes may be varied, said journals I eluding a primary rotor, means journalling said rotor, radially reciprocable pumping elements between said rotors, and means mounting said ring in a plane normal to said axes and for translation along a shift axis lying in said plane, said means comprising journals on said ring aligned on and along said axis, each journal slidably fitting corresponding bearings on said casing, said means constituting the sole support and shifting means for said ring and secondary rotor.

OTTO M. SUMMERS. 

